Tool for friction stir welding

ABSTRACT

A tool for friction stir welding includes a tool part, a shank part and a cap part. The tool part and the shank part have a hexagonal frustum-shaped concave section and a hexagonal frustum-shaped convex section to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation while movement of the tool part with respect to the shank part in a direction around the axis of rotation is restricted, by the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section of the tool part and the shank part are fitted to each other. After the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section are fitted to each other, by the tool part and the shank part being covered by the cap part, the tool part is fixed to the shank part.

TECHNICAL FIELD

An aspect of the present invention relates to a tool for friction stir welding, and particularly, to a tool for friction stir welding including a tool part and a shank part having a front end to which the tool part is fixed.

BACKGROUND ART

In recent years, development of a technology of welding and repair using a friction stir effect is remarkable. Using friction stir welding, a large number of successful examples of welding that could not be performed in the welding of the related art, such as welding between high carbon steels, dissimilar welding of steel and Al alloy, welding between Ti and alloys thereof that requires a high vacuum level for welding, and so on, have been reported. Since friction stir welding is a technology in which Al is used as a target of a material to be welded at the beginning of development, a material that can be relatively easily available, for example, tool steel or the like, can be used for the tool that is used. For this reason, problems related to the tool are focused on a shape of a probe or a shoulder that exerts an influence on a joint, such as a plastic flow, stirring efficiency, or the like.

Meanwhile, in recent years, developments in friction stir welding have been remarkable in a technology of welding or repairing a steel material, a Ti-based alloy or a Ni alloy having a melting point about 1000° C. higher than that of AL When these materials are welded or repaired, a tool having strength against high temperatures and good abrasion resistance is needed. Until now tools having high performance at high temperatures such as ceramic-based tools obtained by sintering cBN (cubic boron nitride) or Si₃N₄ (silicon nitride), metal-based tools such as Ni-based alloys, Co-based alloys, Mo-based alloys, W-based alloys, Ir-based alloys, or the like, and so on, have been developed, and welding of metals having a high melting point come to be realize.

Since such a tool formed of an Ir-based alloy or the like is generally expensive, a technique of manufacturing only the tool that partially contributes to welding or repair and a holder configured to hold the tool using an inexpensive material and assembling the tool portion and the holder is employed. For example, in Patent Document 1, a tool for friction stir welding having a cutout as a locking section formed at a rear section side of the tool that is detachably attached to a shank part is disclosed. An accommodating section into which a rear section side of the tool having the locking section is inserted is formed in the shank part formed of tool steel or dies steel. As the rear section side of the tool is inserted into the accommodating section of the shank part and a screw that is screwed thereinto is pressed against the locking section of the tool inserted into the accommodating section from a side surface of the shank part, the tool is fixed to the shank part.

PRIOR ART DOCUMENTS Patent Document

Patent Document 1: Japanese Published Unexamined Patent Application, First Publication No. 2005-199281

SUMMARY OF INVENTION Problems to be Resolved by the Invention

Incidentally, when the metal having a high melting point is welded, heat is transferred to not only the tool but also the holder that holds the tool, and further, high torsional stress is applied thereto. These become causes of burning and/or biting between the tool and the holder, and detachment of the tool may be difficult. In addition, when the tool and the holder are assembled by a method such as shrinkage fitting or the like, the fitting may become loose due to heating, and a rotational force from the holder fixed to a power source may not be sufficiently transmitted to the tool. In addition, the tool sometimes easily falls out of the holder too easily.

In this technical field, it is desired to provide a tool for friction stir welding capable of more reliably fixing a tool part to a shank part and easily detaching the tool part from the shank part.

Means of Solving the Problems

An aspect of the present invention is a tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a cap part configured to cover the tool part and the shank part, wherein portions in the tool part and the shank part at which the tool part and the shank part contact each other have at least one from between a convex section and a concave section, in order to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction around the axis of rotation of the shank part is restricted, by the convex section and the concave section of the tool part and the shank part being fitted to each other, and after the convex section and the concave section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part, by the tool part and the shank part being covered by the cap part.

According to the above-mentioned configuration, in the tool for friction stir welding, when the tool part is fixed to the shank part by the cap part, since movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part is restricted by the convex section and the concave section that are fitted to each other and movement of the tool part with respect to the shank part in the direction parallel to the axis of rotation of the shank part is restricted by the cap part, it is possible to reliably prevent the tool part from being deviated with respect to the shank part in the direction around the axis of rotation of the shank part upon rotation of the shank part, fixation of the tool part and the shank part from being loosened, and the tool part from falling out of the shank part.

Meanwhile, when the cap part is detached, even when the convex section and the concave section are fitted to each other, since the tool part can move with respect to the shank part in the direction parallel to the axis of rotation of the shank part, the tool part can be easily detached from the shank part.

In addition, another aspect of the present invention is a tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a screw having a groove formed at its outer periphery thereof for fixing the tool part to the front end of the shank part, wherein portions in the tool part and the shank part at which the tool part and the shank part contact each other have at least one from between a convex section and a concave section, in order to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction around the axis of rotation of the shank part is restricted, by the convex section and the concave section of the tool part and the shank part being fitted to each other, the shank part has a shank part hole section wherein the screw is capable of reaching the tool part fixed to the front end of the shank part passing through the shank part, the tool part has a tool part screw hole section having a groove, at an inner periphery, meshing with the groove of the outer periphery of the screw passing through the shank part hole section, and after the convex section and the concave section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part, by the groove of the outer periphery of the screw passed through the shank part hole section meshing with the groove of the inner periphery of the tool part screw hole section.

According to the above-mentioned configuration, in the tool for friction stir welding, after the convex section and the concave section of the tool part and the shank part are fitted to each other, as the screw passing through the shank part hole section is screwed into the tool part screw hole section, since movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part is restricted by the convex section and the concave section that are fitted to each other, the groove of the outer periphery of the screw is meshed with the groove of the inner periphery of the tool part screw hole section and the tool part is pulled and fixed to the shank part.

Since movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part is restricted by the convex section and the concave section that are fitted to each other and movement of the tool part with respect to the shank part in the direction parallel to the axis of rotation of the shank part is restricted by the screw, it is possible to reliably prevent the tool part from being deviated with respect to the shank part in the direction around the axis of rotation of the shank part upon rotation of the shank part, fixation of the tool part and the shank part from being loosened, and the tool part from falling out of the shank part.

Meanwhile, in a state in which movement of the screw in the direction parallel to the axis of rotation of the shank part is restricted, as the screw is rotated away from the tool part screw hole section, while movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part is restricted by the convex section and the concave section that are fitted to each other, since the tool part can move with respect to the shank part in the direction parallel to the axis of rotation of the shank part, the groove of the outer periphery of the screw is meshed with the groove of the inner periphery of the tool part screw hole section, and the tool part is detached from the shank part by applying the force in the direction away from the shank part. Accordingly, the tool part can be easily detached from the shank part.

In this case, the tool may have a groove with an inner diameter larger than an inner diameter of the tool part screw hole section in an inner periphery of the shank part hole section, and the groove may be capable of screwing in a tool part detachment screw having a groove on its outer periphery meshing with the groove of the inner periphery of the shank part hole section.

According to the above-mentioned configuration, as the groove having a larger diameter than the tool part screw hole section is formed in the shank part hole section and the tool part detachment screw having a diameter set to be meshed with the groove is screwed thereinto, the tool part is pushed out. Accordingly, the tool part can be easily detached from the shank part.

In addition, the groove of the outer periphery of the screw and the groove of the inner periphery of the tool part screw hole section may be formed such that the screw moves in an inward direction of the tool part screw hole section when the screw is rotated in the same direction as the rotational direction of the shank part.

According to the above-mentioned configuration, upon rotation of the shank part, since the force is applied in the direction in which the screw moves in the inward direction of the tool part screw hole section, it is possible to more effectively prevent fixation of the tool part and the shank part from being loosened and the tool part from falling out of the shank part as the screw is loosened.

In addition, the convex section may be a shape protruding in either a polygonal conical shape or a polygonal frustum shape, and the concave section may be a shape recessed in either a polygonal conical shape or a polygonal frustum shape.

According to the above-mentioned configuration, the tool part can easily move with respect to the shank part in the direction parallel to the axis of rotation of the shank part while restricting movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part due to the simple shape.

In addition, the convex section may be a protruding shape as a key, and the concave section may have a recessed shape as a key groove.

According to the above-mentioned configuration, the tool part can easily move with respect to the shank part in the direction parallel to the axis of rotation of the shank part while securely restricting movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part due to the simple shape.

In addition, the convex section may have a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and the concave section may have a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation.

According to the above-mentioned configuration, as the surfaces perpendicular to the direction around the axis of rotation abut each other, the tool part can move with respect to the shank part in the direction parallel to the axis of rotation of the shank part while securely restricting movement of the tool part with respect to the shank part in the direction around the axis of rotation of the shank part.

In addition, the convex section may have a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation, and the concave section may have a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and the tool may be further provided with a nut having a groove at its inner periphery meshing with the groove of the outer periphery of the screw, the nut having an outer diameter larger than an inner diameter of the shank part hole section, wherein the screw passes through the nut while the groove of the outer periphery of the screw and the groove of the inner periphery of the nut are meshed with each other, the convex section and the concave section of the tool part and the shank part are fitted to each other, and after the groove of the outer periphery of the screw passing through the shank part hole section is meshed with the groove of the inner periphery of the tool part screw hole section, in a state in which the shank part is disposed between the tool part and the nut, the tool part may be fixed to the front end of the shank part by the nut being rotated in a direction in which the nut and the tool part approach each other, and the tool part may be detached from the front end of the shank part by the screw being rotated in a direction in which surfaces perpendicular to the direction around the axis of rotation of the serrated shapes fitted to each other separate from each other, after the nut is rotated in a direction in which the nut and the tool part recede from each other.

In the above-mentioned configuration, as the screw is screwed into the tool part through the shank part to fasten the nut, the tool part is reliably fixed to the front end of the shank part, and then the nut is loosened to rotate the screw, the serrated inclined surface of the tool part and the serrated inclined surface of the shank part slide in opposite directions, and the tool part is detached from the shank part by applying the force in the direction away from the shank part. Accordingly, the tool part can be detached from the shank part.

In addition, in the case that the convex section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation, and the concave section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, after the screw is removed from the tool part screw hole section and the shank part hole section, a tool part detachment screw having a groove at its outer periphery meshing with the groove of the inner periphery of the tool part screw hole section passes through the shank part hole section, and the groove of the outer periphery of the tool part detachment screw is meshed with the groove of the inner periphery of the tool part screw hole section, and the tool part may be detached from the front end of the shank part by the tool part detachment screw being rotated in a direction in which surfaces perpendicular to the direction around the axis of rotation of the serrated shapes fitted to each other separate from each other.

In the above-mentioned configuration, as the screw is screwed into the shank part and the tool part, the tool part can be reliably fixed to the front end of the shank part. Then, as the screw is detached from the shank part, the tool part detachment screw is screwed into the tool part screw hole section through the shank part hole section and the screw is further rotated, the serrated inclined surface of the tool part and the serrated inclined surface of the shank part slide together, and the tool part is detached from the shank part by applying the force in the direction separating from the shank part. Accordingly, the tool part can be easily detached from the shank part.

In addition, another aspect of the present invention is a tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a sliding restriction member fixed to a portion at which the tool part and the shank part contact each other, wherein a portion of the tool part and the shank part in which the tool part and the shank part contact each other have at least one from between a dovetail-shaped section protruding in a trapezoidal shape and a dovetail groove section recessed in a trapezoidal shape, the dovetail-shaped section protruding in a trapezoidal shape and the dovetail groove section recessed in a trapezoidal shape enabling slide movement of the tool part with respect to the shank part in a direction perpendicular to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction parallel to the axis of rotation of the shank part is restricted by the dovetail-shaped section and the dovetail groove section of the tool part and the shank part being fitted to each other, and after the dovetail-shaped section and the dovetail groove section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part so as to restrict slide movement of the tool part with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part, by the sliding restriction member being fixed to the portion at which the tool part and the shank part contact each other.

According to the above-mentioned configuration, when the sliding restriction member is fixed to the portion at which the tool part and the shank part come in contact with each other, since movement of the tool part with respect to the shank part in the direction parallel to the axis of rotation of the shank part by the dovetail-shaped section and the dovetail groove section that are fitted to each other and sliding movement of the tool part with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part is restricted by the sliding restriction member, upon rotation of the shank part, it is possible to reliably prevent fixation of the tool part and the shank part from being loosened and the tool part from falling out of the shank part. Meanwhile, when the sliding restriction member is detached, even when the dovetail-shaped section and the dovetail groove section are fitted to each other, since the tool part can move with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part, the tool part can be easily detached from the shank part.

In this case, the tool may further comprise a detachment member receiving section capable of having attached thereto a detachment member for applying a force such that the tool part slides with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part when the dovetail-shaped section and the dovetail groove section of the tool part and the shank part are fitted to each other and the sliding restriction member is not fixed to the portion at which the tool part and the shank part contact each other.

According to the above-mentioned configuration, as the detachment member is attached to the detachment member receiving section and a force is applied by the detachment member such that the tool part slides with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part, even when the tool part is hard to remove, the tool part can be easily detached from the shank part.

Advantageous Effects of the Invention

According to the tool for friction stir welding of the above-mentioned aspects and other aspects of the present invention, loosening of fixation between the tool part and the shank part and removal of the tool part from the shank part can be reliably prevented, and the tool part can be easily detached from the shank part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing a shank part, a tool part and a cap part according to a first embodiment.

FIG. 2 is a plan view of the tool part of FIG. 1 when seen from a direction of an arrow A.

FIG. 3 is a side view showing a shank part, a tool part and a cap part according to a second embodiment.

FIG. 4 is a plan view of the tool part of FIG. 3 when seen from a direction of an arrow B.

FIG. 5 is a side view showing a shank part, a tool part and a cap part according to a third embodiment.

FIG. 6 is a plan view of the tool part of FIG. 5 when seen from a direction of an arrow C.

FIG. 7 is a side view showing a shank part, a tool part and a cap part according to a fourth embodiment.

FIG. 8 is a plan view of the tool part of FIG. 7 when seen from a direction of an arrow D.

FIG. 9 is a side view showing a screw, a shank part and a tool part according to a fifth embodiment.

FIG. 10 is a plan view of the tool part of FIG. 9 when seen from a direction of an arrow E.

FIG. 11 is a longitudinal cross-sectional view showing a state in which the tool part is fixed to the shank part using the screw of FIG. 9.

FIG. 12 is a longitudinal cross-sectional view showing a state in which the screw is detached from the state of FIG. 11 and a tool part detachment screw is screwed into the shank part.

FIG. 13 is a longitudinal cross-sectional view showing a state in which the tool part is detached from the shank part as the tool part detachment screw is screwed further thereinto from the state of FIG. 12.

FIG. 14 is a side view showing a screw, a shank part and a tool part according to a sixth embodiment.

FIG. 15 is a plan view of a tool for friction stir welding of FIG. 14 when seen from a direction of an arrow F.

FIG. 16 is a side view showing a screw, a shank part and a tool part according to a seventh embodiment.

FIG. 17 is a plan view of a tool for friction stir welding of FIG. 16 when seen from a direction of an arrow G.

FIG. 18 is a side view showing a screw, a shank part and a tool part according to an eighth embodiment.

FIG. 19 is a plan view of a tool for friction stir welding of FIG. 18 when seen from a direction of an arrow H.

FIG. 20 is a side view showing a screw, a nut, a shank part and a tool part according to a ninth embodiment.

FIG. 21 is a plan view of a tool for friction stir welding of FIG. 20 when seen from a direction of an arrow I.

FIG. 22 is a partial cross-sectional view showing a state in which the tool part is fixed to the shank part using the screw and the nut of FIG. 20.

FIG. 23 is a partial cross-sectional view showing a state in which the nut is rotated away from the tool part from the state of FIG. 22.

FIG. 24 is a partial cross-sectional view showing a state in which the screw is rotated from the state of FIG. 23 to detach the tool part from the shank part in a direction in which a serrated vertical surface of the tool part and a serrated vertical surface of the shank part are separated from each other.

FIG. 25 is a side view showing a screw, a shank part and a tool part according to a tenth embodiment.

FIG. 26 is a plan view of a tool for friction stir welding of FIG. 25 when seen from a direction of an arrow J.

FIG. 27 is a partial cross-sectional view showing a state in which the tool part is fixed to the shank part using the screw of FIG. 25.

FIG. 28 is a partial cross-sectional view showing a state in which the screw is removed from the state of FIG. 27 and a tool part detachment screw is screwed into the tool part through the shank part.

FIG. 29 is a partial cross-sectional view showing a state in which the tool part detachment screw is rotated from the state of FIG. 28 to detach the tool part from the shank part in a direction in which a serrated vertical surface of the tool part and a serrated vertical surface of the shank part are separated from each other.

FIG. 30 is a perspective view showing a shank part, a tool part and a lid according to an eleventh embodiment.

FIG. 31 is a plan view of the assembled shank part, tool part and lid of FIG. 30 when seen from a direction of an arrow K.

FIG. 32 is a cross-sectional view taken along line L-L of FIG. 31.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, a tool for friction stir welding 10 a according to a first embodiment of the present invention includes a shank part 100 a, a tool part 200 a and a cap part 300.

The shank part 100 a has a columnar shape as a whole. The shank part 100 a fixes the tool part 200 a to a front end thereof at a lower end in FIG. 1, and is rotated about an axis of rotation 11 by a power source (not shown) together with the tool part 200 a. The shank part 100 a can be manufactured using a relatively inexpensive material such as tool steel or the like. A screw hole section configured to fix the cap part 300 using a screw may be formed at a circumferential edge or an outer periphery of the front end of the shank part 100 a. Alternatively, a groove configured to fix the cap part 300 may be formed in the outer periphery of the front end of the shank part 100 a.

The tool part 200 a is fixed to the front end of the shank part 100 a, and abuts a workpiece while rotating. The tool part 200 a has a columnar shoulder 201 protruding from a conical frustum or columnar base section 205 at the front end portion abutting the workpiece. While the base section 205 will be described using a conical frustum base section in FIG. 1 and the other embodiments described below, the base section may be variously modified to a shape such as a columnar shape or the like. A conical frustum probe 202 having a bottom surface with a smaller diameter than the shoulder 201 protrudes from a center of the front end of the shoulder 201. When the workpiece having a high melting point and formed of a steel material, a Ti-based alloy, a Ni alloy, or the like, is welded, the tool part 200 a is manufactured using an Ir-based alloy or the like. In the embodiment, since the tool part 200 a has a minimum size that enables the friction stir welding, even when the tool part is manufactured using a relatively expensive material such as an Ir alloy or the like, manufacturing cost can be reduced.

The cap part 300 has a cylindrical shape as a whole. The cap part 300 may be manufactured using a relatively inexpensive material such as tool steel or the like. The cap part 300 has a cap part inner surface 301. The cap part inner surface 301 has a shape corresponding to a shape of the front end of the shank part 100 a. The cap part inner surface 301 has a reduced diameter section 302 having an inner diameter reduced at the end portion. The reduced diameter section 302 has a shape corresponding to a shape of the conical frustum or columnar base section 205 of the tool part 200 a, and an inner diameter smaller than the outer diameter of the conical frustum or columnar base section 205 and equal to or larger than the outer diameter of the shoulder 201. A hole section corresponding to a screw hole section of the shank part 100 a may be formed in the cap part 300 to be fixed to the front end of the shank part 100 a. Alternatively, in order to fix the cap part to the front end of the shank part 100 a, a groove corresponding to the groove formed in the outer periphery of the front end of the shank part 100 a may be formed in the cap part inner surface 301.

A hexagonal frustum-shaped concave section 121 recessed in a hexagonal frustum shape is formed in the front end of the shank part 100 a. The side surface of the hexagonal frustum-shaped concave section 121 is inclined toward the axis of rotation 11 of the shank part 100 a while reaching the inside of the shank part 100 a from the front end of the shank part 100 a. Further, the hexagonal frustum-shaped concave section 121 is not limited to the hexagonal frustum shape but may have shapes of a quadrangular pyramid, an octagonal pyramid or other polygonal pyramids, and a quadrangular frustum, an octagonal frustum or other polygonal frustums.

As shown in FIGS. 1 and 2, a hexagonal frustum-shaped convex section 211 corresponding to a shape of the hexagonal frustum-shaped concave section 121 of the shank part 100 a is formed at a portion of the base section 205 of the tool part 200 a that comes in contact with the shank part 100 a. The side surface of the hexagonal frustum-shaped convex section 211 is inclined toward the axis of rotation 11 of the shank part 100 a that serves as an axis of rotation of the tool part 200 a as separated from the base section 205 of the tool part 200 a. Further, the hexagonal frustum-shaped convex section 211 is not limited to the hexagonal frustum shape but may have shapes of a quadrangular pyramid, an octagonal pyramid or other polygonal pyramids, and a quadrangular frustum, an octagonal frustum or other polygonal frustums.

Hereinafter, an action of the tool for friction stir welding 10 a of the embodiment will be described. When the friction stir welding is performed using the tool for friction stir welding 10 a, the hexagonal frustum-shaped concave section 121 of the shank part 100 a and the hexagonal frustum-shaped convex section 211 of the tool part 200 a are fitted to each other. Since both of the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 have a hexagonal frustum shape, movement of the tool part 200 a with respect to the shank part 100 a in a direction parallel to the axis of rotation 11 of the shank part 100 a becomes possible while movement of the tool part 200 a with respect to the shank part 100 a in a direction around the axis of rotation 11 of the shank part 100 a is restricted.

In a state in which the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 are fitted to each other, as the front end of the shank part 100 a and the base section 205 of the tool part 200 a are covered by the cap part 300 attached to the shank part 100 a, the tool part 200 a is fixed to the front end of the shank part 100 a. Here, the shoulder 201 and the probe 202 of the tool part 200 a are exposed from the cap part 300. In this way, the friction stir welding can be performed in a state in which the tool part 200 a is fixed to the front end of the shank part 100 a. When the tool part 200 a is detached from the shank part 100 a, as the cap part 300 is detached from the shank part 100 a and the tool part 200 a, the tool part 200 a can be easily detached from the shank part 100 a. Further, application of a release agent such as BN or the like to the hexagonal frustum-shaped concave section 121, the hexagonal frustum-shaped convex section 211 and the cap part inner surface 301 that come in contact with each other is effective to prevent burning.

According to the embodiment, the tool for friction stir welding 10 a includes the tool part 200 a abutting the workpiece while rotating, the shank part 100 a having the front end to which the tool part 200 a is fixed and rotated together with the tool part 200 a, and the cap part 300 configured to cover the tool part 200 a and the shank part 100 a. The hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 are provided at portions of the tool part 200 a and the shank part 100 a at which the tool part 200 a and the shank part 100 a come in contact with each other, such that the tool part 200 a can move with respect to the shank part 100 a in the direction parallel to the axis of rotation of the shank part 100 a while movement of the tool part 200 a with respect to the shank part 100 a in the direction around the axis of rotation 11 of the shank part 100 a is restricted as the tool part and the shank part are fitted to each other. After the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 of the tool part 200 a and the shank part 100 a are fitted to each other, as the tool part 200 a and the shank part 100 a are covered by the cap part 300, the tool part 200 a is fixed to the front end of the shank part 100 a.

For this reason, when the tool part 200 a is fixed to the shank part 100 a by the cap part 300, since movement of the tool part 200 a with respect to the shank part 100 a in the direction around the axis of rotation 11 of the shank part 100 a is restricted by the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 that are fitted to each other and movement of the tool part 200 a with respect to the shank part 100 a in the direction parallel to the axis of rotation 11 of the shank part 100 a is restricted by the cap part 300, it is possible to reliably prevent the tool part 200 a from being deviated with respect to the shank part 100 a in the direction around the axis of rotation 11 of the shank part 100 a upon rotation of the shank part 100 a, fixation of the tool part 200 a and the shank part 100 a from being loosened, or the tool part 200 a from falling out of the shank part 100 a.

Meanwhile, when the cap part 300 is detached, even though the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 are fitted to each other, since the tool part 200 a can move with respect to the shank part 100 a in the direction parallel to the axis of rotation 11 of the shank part 100 a, the tool part 200 a can be easily detached from the shank part 100 a.

In addition, in the embodiment, the hexagonal frustum-shaped concave section 121 is recessed in a hexagonal frustum shape, and the hexagonal frustum-shaped convex section 211 protrudes in a hexagonal frustum shape. For this reason, the tool part 200 a can be easily moved with respect to the shank part 100 a in the direction parallel to the axis of rotation 11 of the shank part 100 a while restricting movement of the tool part 200 a with respect to the shank part 100 a in the direction around the axis of rotation 11 of the shank part 100 a due to the simple shape. In addition, in the embodiment, since the hexagonal frustum-shaped convex section 211 protrudes from the tool part 200 a abutting the workpiece and a length of the tool part 200 a along the axis of rotation 11 is increased, strength of the tool part 200 a can be improved.

Hereinafter, a second embodiment of the present invention will be described. As shown in FIGS. 3 and 4, a tool for friction stir welding 10 b of the embodiment is distinguished from the first embodiment in that the same hexagonal frustum-shaped convex section 111 as the hexagonal frustum-shaped convex section 211 of the tool part 200 a of the first embodiment is provided at a shank part 100 b and the same hexagonal frustum-shaped concave section 221 as the hexagonal frustum-shaped concave section 121 of the shank part 100 a of the first embodiment is provided at a tool part 200 b. The other configurations and actions of the tool for friction stir welding 10 b are the same as the first embodiment.

In the embodiment, since the hexagonal frustum-shaped concave section 221 is recessed in the tool part 200 b abutting the workpiece, even when the tool part is manufactured using a relatively expensive material such as an Ir alloy or the like, manufacturing cost can be reduced while reducing an amount of the material used.

Hereinafter, a third embodiment of the present invention will be described. As shown in FIG. 5, in a tool for friction stir welding 10 c of the embodiment, a conical frustum concave section 122 recessed in a conical frustum shape is formed at a center of a front end of a shank part 100 c. A side surface of the conical frustum concave section 122 is inclined toward the axis of rotation 11 of the shank part 100 c while reaching the inside of the shank part 100 c from the front end of the shank part 100 c. In addition, keys 131 protruding in a direction parallel to the axis of rotation 11 at positions of 0° and 180° around the axis of rotation 11 are formed at a circumferential edge of the front end of the shank part 100 c. These keys 131 may be disposed at positions of 0°, 90°, 180° and 270° around the axis of rotation 11 in a cross shape. In addition, an arbitrary number of keys 131 may be disposed.

As shown in FIGS. 5 and 6, a conical frustum convex section 212 corresponding to a shape of the conical frustum concave section 122 of the shank part 100 c is formed at a portion of a base section 205 of a tool part 200 c that comes in contact with the shank part 100 c. The side surface of the conical frustum convex section 212 is inclined toward the axis of rotation 11 of the shank part 100 c serving as the axis of rotation of the tool part 200 c while being separated from the base section 205 of the tool part 200 c. Key grooves 232 recessed in a direction parallel to the axis of rotation 11 at positions of 0° and 180° around the axis of rotation 11 are formed in a circumferential edge of the base section 205 of the tool part 200 c to correspond to shapes of the keys 131 of the shank part 100 c. These key grooves 232 may be disposed at positions of 0°, 90°, 180° and 270° around the axis of rotation 11 in a cross shape. In addition, an arbitrary number of key grooves 232 may be disposed.

Hereinafter, an action of the tool for friction stir welding 10 c of the embodiment will be described. When the friction stir welding is performed using the tool for friction stir welding 10 c, the conical frustum concave section 122 of the shank part 100 c and the conical frustum convex section 212 of the tool part 200 c, and the key 131 of the shank part 100 c and the key groove 232 of the tool part 200 c are fitted to each other, respectively. Since both of the conical frustum concave section 122 and the conical frustum convex section 212 have a truncated cone shape, the tool part 200 c can move with respect to the shank part 100 c in the direction parallel to the axis of rotation 11 of the shank part 100 c. Meanwhile, since the key 131 and the key groove 232 are fitted to each other, movement of the tool part 200 c with respect to the shank part 100 c in the direction around the axis of rotation 11 of the shank part 100 c is restricted. Further, a release agent such as BN or the like is applied to the conical frustum concave section 122, the conical frustum convex section 212, the key 131 and the key groove 232 that come in contact with each other to effectively prevent burning.

In a state in which the conical frustum concave section 122 and the conical frustum convex section 212 are fitted to each other and the key 131 and the key groove 232 are fitted to each other, as the front end of the shank part 100 c and the base section 205 of the tool part 200 c are covered by the cap part 300, the tool part 200 c is fixed to the front end of the shank part 100 c. Here, the shoulder 201 and the probe 202 of the tool part 200 c are exposed from the cap part 300. In this way, the friction stir welding can be performed in a state in which the tool part 200 c is fixed to the front end of the shank part 100 c. When the tool part 200 c is detached from the shank part 100 c, as the cap part 300 is detached from the shank part 100 c and the tool part 200 c, the tool part 200 c can be easily detached from the shank part 100 c.

According to the embodiment, since the protruding key 131 and the recessed key groove 232 are provided, the tool part 200 c can move with respect to the shank part 100 c in the direction parallel to the axis of rotation 11 of the shank part 100 c while movement of the tool part 200 c with respect to the shank part 100 c in the direction around the axis of rotation 11 of the shank part 100 c is reliably restricted due to the simple shape. In addition, in the embodiment, since the conical frustum convex section 212 protrudes from the tool part 200 c abutting the workpiece and a length of the tool part 200 c along the axis of rotation 11 is increased, strength of the tool part 200 c can be improved.

Hereinafter, a fourth embodiment of the present invention will be described. As shown in FIGS. 7 and 8, a tool for friction stir welding 10 d of the embodiment is distinguished from the third embodiment in that the same conical frustum convex section 112 and the same key groove 132 as the conical frustum convex section 212 and the key groove 232 of the tool part 200 c of the third embodiment are formed at a shank part 100 d and the same conical frustum concave section 222 and the same key 231 as the conical frustum concave section 122 and the key 131 of the shank part 100 c of the third embodiment are formed at a tool part 200 d. The other configurations and actions of the tool for friction stir welding 10 d are the same as the third embodiment.

In the embodiment, since the conical frustum concave section 222 is recessed in the tool part 200 d abutting the workpiece, even when the tool part is manufactured using a relatively expensive material such as an Ir alloy or the like, manufacturing cost can be reduced by reducing an amount of the material used.

Hereinafter, a fifth embodiment of the present invention will be described. As shown in FIG. 9, a tool for friction stir welding 10 e according to the fifth embodiment of the present invention includes a shank part 100 e, a tool part 200 e and a screw 400 e.

As shown in FIG. 9, the shank part 100 e of the embodiment is distinguished from the first embodiment in that a hole section 141 is provided such that a screw front end portion 402 of the screw 400 e passes through the shank part 100 e to reach the tool part 200 e fixed to the front end of the shank part 100 e. Further, while a groove is not necessary to be formed in the inner periphery of the hole section 141, a groove meshed with a groove 404 of the outer periphery of the screw 400 e may be formed in the inner periphery of the hole section 141. Further, as shown in FIG. 9, a groove 144 having a larger inner diameter than a screw hole section 241 of the tool part 200 e may be formed at the inner periphery of the hole section 141 such that a tool part detachment screw having an outer diameter set to be meshed with the groove 144 is screwed thereinto. In addition, a collar 213 having an inner diameter slightly larger than the outer diameter of the tool part 200 e may be formed in the shank part 100 e. A central axis of the tool part 200 e is easily matched with the axis of rotation 11 of the shank part 100 e by the collar 213. In addition, a load of the screw 400 e configured to connect the shank part 100 e and the tool part 200 e is reduced by the collar 213, and movement of the tool part 200 e from the shank part 100 e upon the friction stir welding can be prevented.

As shown in FIGS. 9 and 10, the tool part 200 e of the embodiment is distinguished from the first embodiment in that the screw hole section 241 has a groove 244 formed in an inner periphery thereof and meshed with the groove 404 of the outer periphery of the screw front end portion 402 of the screw 400 e that passes through the hole section 141.

As shown in FIG. 9, the screw 400 e has the screw front end portion 402 having the groove 404 formed at the outer periphery and configured to fix the tool part 200 e to the front end of the shank part 100 e. A screw head section 401 having a larger diameter than the screw front end portion 402 and the hole section 141 is formed at an opposite side of the screw front end portion 402 of the screw 400 e. A length of the screw 400 e excluding the screw head section 401 corresponds to a length obtained by adding a length of the hole section 141 of the shank part 100 e and a length of the screw hole section 241 of the tool part 200 e. Further, while the groove 404 of the screw front end portion 402 may be formed within a range to be meshed with the groove 244 of the screw hole section 241 of the tool part 200 e, as shown in FIG. 9, the groove 404 may be formed over the entire screw 400 e except for the screw head section 401.

Further, the groove 404 of the outer periphery of the screw 400 e and the groove 244 of the inner periphery of the screw hole section 241 of the tool part 200 e are formed in a direction in which the screw 400 e moves in an inward direction of the screw hole section 241 of the tool part 200 e when the screw 400 e is rotated in the same direction as the rotational direction of the shank part 100 e. For example, when the screw grooves 404 and 244 formed in the screw 400 e and the tool part 200 e are formed in a conventional direction in which the screw 400 e moves in the inward direction of the screw hole section 241 of the tool part 200 e when the screw 400 e is rotated clockwise when seen from the screw head section 401, the rotational direction of the shank part 100 e upon the friction stir welding becomes clockwise when seen from the screw head section 401.

Hereinafter, an action of the tool for friction stir welding 10 e of the embodiment will be described. When the friction stir welding is performed using the tool for friction stir welding 10 e, like the first embodiment, the hexagonal frustum-shaped concave section 121 of the shank part 100 e and the hexagonal frustum-shaped convex section 211 of the tool part 200 e are fitted to each other. Since both of the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 have the hexagonal frustum shape, the tool part 200 e can move with respect to the shank part 100 e in the direction parallel to the axis of rotation 11 of the shank part 100 e while movement of the tool part 200 e with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e is restricted.

In a state in which the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 are fitted to each other, as shown in FIG. 11, as the screw 400 e is inserted into the hole section 141 of the shank part 100 e while being rotated in a direction moving in the inward direction of the screw hole section 241 of the tool part 200 e and the groove 404 of the outer periphery of the screw 400 e that passes through the hole section 141 of the shank part 100 e is meshed with the groove 244 of the inner periphery of the screw hole section 241 of the tool part 200 e, the tool part 200 e is fixed to the front end of the shank part 100 e. In this way, the friction stir welding can be performed in a state in which the tool part 200 e is fixed to the front end of the shank part 100 e. Further, a release agent such as BN or the like is applied to the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211 that come in contact with each other, the screw 400 e and the hole section 141, and the screw hole section 241 to effectively prevent burning. When the tool part 200 e is detached from the shank part 100 e, in a state in which movement of the screw 400 e in the direction parallel to the axis of rotation 11 of the shank part 100 e is restricted, as the screw 400 e is rotated away from the screw hole section 241 of the tool part 200 e, the tool part 200 e can be easily detached from the shank part 100 e.

In addition, as shown in FIG. 9, when the groove 144 having a larger inner diameter than the screw hole section 241 of the tool part 200 e is formed in the hole section 141 of the shank part 100 e, first, the screw 400 e is detached from the tool part 200 e and the shank part 100 e. Next, as shown in FIG. 12, a tool part detachment screw 450 e having a groove 454 formed at an outer periphery thereof and meshed with the groove 144 formed in the inner periphery of the hole section 141 of the shank part 100 e is screwed into the hole section 141. In an example of FIG. 12, when seen from a screw head section 451 of the tool part detachment screw 450 e, as the tool part detachment screw 450 e is rotated clockwise, a screw front end portion 452 of the tool part detachment screw 450 e abuts the tool part 200 e. As shown in FIG. 13, as the tool part detachment screw 450 e is further rotated clockwise when seen from the screw head section 451, the tool part 200 e is pushed out by the screw front end portion 452 of the tool part detachment screw 450 e, and the tool part 200 e is detached from the shank part 100 e.

According to the embodiment, after the hexagonal frustum-shaped convex section 211 and the hexagonal frustum-shaped concave section 121 of the tool part 200 e and the shank part 100 e are fitted to each other, as the screw 400 e passing through the hole section 141 of the shank part 100 e is screwed into the screw hole section 241 of the tool part 200 e, since movement of the tool part 200 e with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e is restricted by the hexagonal frustum-shaped convex section 211 and the hexagonal frustum-shaped concave section 121 that are fitted to each other, the groove 404 of the outer periphery of the screw 400 e is meshed with the groove 244 of the inner periphery of the screw hole section 241 of the tool part 200 e, and the tool part 200 e is pulled and fixed to the shank part 100 e.

Since movement of the tool part 200 e with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e is restricted by the hexagonal frustum-shaped convex section 211 and the hexagonal frustum-shaped concave section 121 that are fitted to each other and movement of the tool part 200 e with respect to the shank part 100 e in the direction parallel to the axis of rotation 11 of the shank part 100 e is restricted by the screw 400 e, it is possible to reliably prevent the tool part 200 e from being deviated with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e upon rotation the shank part 100 e, fixation of the tool part 200 e and the shank part 100 e from being loosened, and the tool part 200 e from falling out of the shank part 100 e.

Meanwhile, in a state in which movement of the screw 400 e in the direction parallel to the axis of rotation 11 of the shank part 100 e is restricted by rotation of the screw 400 e away from the screw hole section 241 of the tool part 200 e, since the tool part 200 e can move with respect to the shank part 100 e in the direction parallel to the axis of rotation 11 of the shank part 100 e, while movement of the tool part 200 e with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e is restricted by the hexagonal frustum-shaped convex section 211 and the hexagonal frustum-shaped concave section 121 that are fitted to each other, the groove 404 of the outer periphery of the screw 400 e is meshed with the groove 244 of the inner periphery of the screw hole section 241 of the tool part 200 e, and the tool part 200 e is detached from the shank part 100 e by applying a force in a direction away from the shank part 100 e. Accordingly, the tool part 200 e can be easily detached from the shank part 100 e.

In addition, as the groove 144 having a larger diameter than the screw hole section 241 of the tool part 200 e is formed in the hole section 141 of the shank part 100 e and the tool part detachment screw 450 e having a diameter set to be meshed with the groove 144 is screwed thereinto, the tool part 200 e is detached from the shank part 100 e by applying a force in a direction away from the shank part 100 e. Accordingly, the tool part 200 e can be easily detached from the shank part 100 e.

In addition, in the embodiment, the groove 404 of the outer periphery of the screw 400 e and the groove 244 of the inner periphery of the screw hole section 241 of the tool part 200 e are configured such that the screw 400 e is moved in the inward direction of the screw hole section 241 of the tool part 200 e when the screw 400 e is rotated in the same direction as the rotational direction of the shank part 100 e. Accordingly, upon rotation of the shank part 100 e, since a force is applied in the direction in which the screw 400 e is moved in the inward direction of the screw hole section 241 of the tool part 200 e, it is possible to effectively prevent fixation of the tool part 200 e and the shank part 100 e from loosening and the tool part 200 e from falling out of the shank part 100 e due to loosening of the screw 400 e.

In addition, in the embodiment, the hexagonal frustum-shaped concave section 121 is recessed in a hexagonal frustum shape, and the hexagonal frustum-shaped convex section 211 protrudes in a hexagonal frustum shape. For this reason, the tool part 200 e can be easily moved with respect to the shank part 100 e in the direction parallel to the axis of rotation 11 of the shank part 100 e while movement of the tool part 200 e with respect to the shank part 100 e in the direction around the axis of rotation 11 of the shank part 100 e is restricted due to the simple shape.

In addition, in the embodiment, since the hexagonal frustum-shaped convex section 211 protrudes from the tool part 200 e abutting the workpiece and a length of the tool part 200 e along the axis of rotation 11 is increased, strength of the tool part 200 e can be improved.

Hereinafter, a sixth embodiment of the present invention will be described. As shown in FIGS. 14 and 15, a tool for friction stir welding 10 f of the embodiment is distinguished from the fifth embodiment in that the same hexagonal frustum-shaped convex section 111 as the hexagonal frustum-shaped convex section 211 of the tool part 200 e of the fifth embodiment is provided at a shank part 100 f and the same hexagonal frustum-shaped concave section 221 as the hexagonal frustum-shaped concave section 121 of the shank part 100 e of the fifth embodiment is provided at a tool part 200 f.

In addition, as shown in FIG. 14, the embodiment is distinguished from the fifth embodiment in that an increased hole diameter section 142 having a larger inner diameter than the hole section 141 is formed at the hole section 141 of the shank part 100 f close to the screw head section 401. For this reason, a length of a screw 400 f excluding the screw head section 401 corresponds to a length obtained by adding a length of the hole section 141 of the shank part 100 f smaller than that of the fifth embodiment and a length of the screw hole section 241 of the tool part 200 f, and is smaller than that of the screw 400 e of the fifth embodiment. The other configurations and actions of the tool for friction stir welding 10 f are the same as the fifth embodiment.

In the embodiment, since the hexagonal frustum-shaped concave section 221 is recessed in the tool part 200 f abutting the workpiece, even when the tool part is manufactured using a relatively expensive material such as an Ir alloy or the like, manufacturing cost can be reduced by reducing a use amount of the material. In addition, since the screw head section 401 of the screw 400 f is accommodated in the increased hole diameter section 142, when exposure of the screw head section 401 from the shank part 100 f is not preferable due to a situation in a facility that performs the friction stir welding, it is possible to prevent exposure of the screw head section 401 from the shank part 100 f.

Hereinafter, a seventh embodiment of the present invention will be described. As shown in FIGS. 16 and 17, a tool for friction stir welding 10 g of the embodiment is distinguished from the sixth embodiment in that, like the third embodiment, the conical frustum concave section 122 and the key 131 are provided at a shank part 100 g and the conical frustum convex section 212 and the key groove 232 are provided at a tool part 200 g. A length of a screw 400 g excluding the screw head section 401 corresponds to a length obtained by adding a length of the hole section 141 of the shank part 100 g smaller than that of the fifth embodiment and a length of the screw hole section 241 of the tool part 200 g, and is smaller than that of the screw 400 e of the fifth embodiment. The other configurations and actions of the tool for friction stir welding 10 g are the same as the third embodiment and the sixth embodiment.

In the embodiment, since the protruding key 131 and the recessed key groove 232 are provided, the tool part 200 g can move with respect to the shank part 100 g in the direction parallel to the axis of rotation 11 of the shank part 100 g while movement of the tool part 200 g with respect to the shank part 100 g in the direction around the axis of rotation 11 of the shank part 100 g is reliably restricted due to the simple shape.

In addition, in the embodiment, since the conical frustum convex section 212 protrudes from the tool part 200 g abutting the workpiece and the length of the tool part 200 g along the axis of rotation 11 is increased, strength of the tool part 200 g can be improved.

Hereinafter, an eighth embodiment of the present invention will be described. As shown in FIGS. 18 and 19, a tool for friction stir welding 10 h of the embodiment is distinguished from the fifth embodiment in that, like the fourth embodiment, the conical frustum convex section 112 and the key groove 132 are provided at a shank part 100 h and the conical frustum concave section 222 and the key 231 are provided at a tool part 200 h. A length of a screw 400 h excluding the screw head section 401 corresponds to a length obtained by adding a length of the hole section 141 of the shank part 100 h and a length of the screw hole section 241 of the tool part 200 h. The other configurations and actions of the tool for friction stir welding 10 h are the same as the fourth embodiment and the fifth embodiment.

According to the embodiment, since the protruding key 231 and the recessed key groove 132 are provided, the tool part 200 h can move with respect to the shank part 100 h in the direction parallel to the axis of rotation 11 of the shank part 100 h while movement of the tool part 200 h with respect to the shank part 100 h in the direction around the axis of rotation 11 of the shank part 100 h is reliably restricted due to the simple shape.

In addition, in the embodiment, since the conical frustum concave section 222 is recessed in the tool part 200 h abutting the workpiece, even when the tool part is manufactured using a relatively expensive material such as an Ir alloy or the like, manufacturing cost can be reduced by reducing an amount of the material used.

Hereinafter, a ninth embodiment of the present invention will be described. As shown in FIG. 20, a tool for friction stir welding 10 i of the embodiment is distinguished from the fifth embodiment in that a serrated shape 151 protruding in a serrated shape and including a vertical surface 153 parallel to the axis of rotation 11 of the shank part 100 i and perpendicular to the direction around the axis of rotation 11 is provided at a front end of a shank part 100 i. In addition, the embodiment is distinguished from the fifth embodiment in that a length of a screw 400 i excluding the screw head section 401 is sufficiently greater than a length obtained by adding a length of the hole section 141 of the shank part 100 i and a length of the screw hole section 241 of a tool part 200 i, and further, a nut 460 is provided at the screw head section 401 side of the screw 400 i. The nut 460 has a groove formed in the inner periphery and meshed with the groove 404 of the outer periphery of the screw 400 i, and has an outer diameter larger than the inner diameter of the hole section 141. Four serrated shapes 151 that include the common vertical surface 153 are disposed at the front end of the shank part 100 i.

In addition, as shown in FIGS. 20 and 21, the tool for friction stir welding 10 i of the embodiment is distinguished from the fifth embodiment in that a serrated shape 251 including the vertical surface 253 parallel to the axis of rotation 11 of the shank part 100 i and perpendicular to the direction around the axis of rotation 11 is provided at a bottom section of the base section 205 of the tool part 200 i. The serrated shape 251 of the tool part 200 i has a shape corresponding to a shape of the serrated shape 151 of the shank part 100 i, and is disposed to correspond to the disposition of the serrated shape 151 of the shank part 100 i. The four serrated shapes 251 that include the common vertical surface 253 are disposed at the bottom section of the base section 205 of the tool part 200 i. Further, the shapes and the numbers of the serrated shapes 151 and the serrated shapes 251 may be arbitrarily selected.

Hereinafter, an action of the tool for friction stir welding 10 i of the embodiment will be described. When the friction stir welding is performed using the tool for friction stir welding 10 i, like the fifth embodiment, the serrated shape 151 of the shank part 100 i and the serrated shape 251 of the tool part 200 i are fitted to each other.

The serrated shape 151 includes the vertical surface 153 parallel to the axis of rotation 11 of the shank part 100 i and perpendicular to the direction around the axis of rotation 11, and the serrated shape 251 includes the vertical surface 253 parallel to the axis of rotation 11 of the shank part 100 i and perpendicular to the direction around the axis of rotation 11. For this reason, the tool part 200 i can move with respect to the shank part 100 i in the direction parallel to the axis of rotation 11 of the shank part 100 i while movement of the tool part 200 i with respect to the shank part 100 i in the direction around the axis of rotation 11 of the shank part 100 i is reliably restricted.

In the embodiment, as the vertical surfaces 153 and 253 perpendicular to the direction around the axis of rotation 11 abut each other, when seen from the screw head section 401 inserted after that, movement of the tool part 200 i with respect to the shank part 100 i in a counterclockwise direction is reliably restricted. Accordingly, the rotational direction of the shank part 100 i upon the friction stir welding becomes clockwise when seen from the screw head section 401.

As shown in FIG. 20, the screw 400 i passes through the nut 460 while the groove 404 of the outer periphery of the screw 400 i and the groove of the inner periphery of the nut 460 are meshed with each other. In a state in which the shank part 100 i is disposed between the tool part 200 i and the nut 460, the groove 404 of the outer periphery of the screw 400 i that passed through the hole section 141 is meshed with the groove 244 of the inner periphery of the screw hole section 241. As shown in FIG. 22, as the nut 460 is rotated in a direction in which the nut 460 and the tool part 200 i approach each other, the tool part 200 i is fixed to the front end of the shank part 100 i.

When the tool part 200 i is detached from the shank part 100 i, first, as shown in FIG. 23, the nut 460 is rotated in the direction in which the nut 460 and the tool part 200 i move away from each other. Accordingly, the tool part 200 i and the screw 400 i can move in the direction parallel to the axis of rotation 11 of the shank part 100 i.

Next, as shown in FIG. 24, the screw 400 i is rotated in the direction in which the vertical surface 153 of the serrated shape 151 of the shank part 100 i and the vertical surface 253 of the serrated shape 251 of the tool part 200 i that are fitted to each other are separated from each other. The direction becomes clockwise when seen from the screw head section 401, and becomes a direction in which the screw 400 i is screwed into the screw hole section 241. An inclined surface of the serrated shape 251 of the tool part 200 i slides along an inclined surface of the serrated shape 151 of the shank part 100 i, the tool part 200 i is pushed out of the shank part 100 i while rotating, and the tool part 200 i is detached from the front end of the shank part 100 i.

Accordingly, the tool part 200 i is reliably fixed to the front end of the shank part 100 i by screwing the screw 400 i into the shank part 100 i and the tool part 200 i to fasten the nut 460, and then the nut 460 is loosened and the screw 400 i is rotated clockwise when seen from the screw head section 401, the inclined surface of the serrated shape 251 of the tool part 200 i and the inclined surface of the serrated shape 151 of the shank part 100 i slide and the tool part 200 i is detached from the shank part 100 i by applying a force in a direction away from the shank part 100 i. Accordingly, the tool part 200 i can be easily detached from the shank part 100 i. Further, a release agent such as BN or the like is applied to the serrated shape 151, the serrated shape 251, the screw 400 i, the hole section 141 and the screw hole section 241 that come in contact with each other to effectively prevent burning.

Hereinafter, a tenth embodiment of the present invention will be described. As shown in FIG. 25, a tool for friction stir welding 10 j of the embodiment is distinguished from the ninth embodiment in that a serrated convex section 161 protruding in a serrated shape and including a vertical surface 163 parallel to the axis of rotation 11 of the shank part 100 j and perpendicular to the direction around the axis of rotation 11 is provided at a columnar concave section 124 recessed in a columnar shape of a front end of a shank part 100 j. In addition, the embodiment is distinguished from the ninth embodiment in that the increased hole diameter section 142 having a larger inner diameter than the hole section 141 is formed in the hole section 141 of the shank part 100 j close to the screw head section 401. For this reason, a length of a screw 400 j excluding the screw head section 401 corresponds to a length obtained by adding a length of the hole section 141 of the shank part 100 j smaller than that of the ninth embodiment and a length of the screw hole section 241 of a tool part 200 j and is smaller than that of the screw 400 i of the ninth embodiment, and further, the nut 460 is not provided. In addition, the groove 404 of the screw 400 j and the groove 244 of the screw hole section 241 are formed in a direction in which the screw 400 j is screwed into the screw hole section 241 when the screw 400 j is rotated counterclockwise when seen from the screw head section 401.

In addition, as shown in FIGS. 25 and 26, the tool for friction stir welding 10 j of the embodiment is distinguished from the ninth embodiment in that a serrated concave section 262 recessed in a serrated shape and including a vertical surface 263 parallel to the axis of rotation 11 of the shank part 100 j and perpendicular to the direction around the axis of rotation 11 is provided at the bottom section of the base section 205 of the tool part 200 j. Further, the shapes and the numbers of the serrated convex section 161 and the serrated concave section 262 may be arbitrarily selected.

A configuration and an action of the tool for friction stir welding 10 j will be described. As shown in FIG. 27, as the screw 400 j is screwed into the shank part 100 j and the tool part 200 j, the tool part 200 j is pulled to the shank part 100 j, and the tool part 200 j can be reliably fixed to the front end of the shank part 100 j.

When the tool part 200 j is detached from the shank part 100 j, first, the screw 400 j is detached from the shank part 100 j. Next, as shown in FIG. 28, a tool part detachment screw 450 j having a sufficiently greater length than the screw 400 j and the same groove 454 as the screw 400 j formed in the outer periphery is screwed into the hole section 141 of the shank part 100 j and the screw hole section 241 of the tool part 200 j counterclockwise when seen from the screw head section 451. Accordingly, the tool part 200 j and the tool part detachment screw 450 j can move in the direction parallel to the axis of rotation 11 of the shank part 100 j.

Further, as shown in FIG. 29, as the tool part detachment screw 450 j is rotated counterclockwise when seen from the screw head section 451, the tool part 200 j is rotated in a direction in which the vertical surfaces 163 and 263 that are fitted to each other are separated from each other. The inclined surface of the serrated concave section 262 of the tool part 200 j and the inclined surface of the serrated convex section 161 of the shank part 100 j slide and the tool part 200 j is detached from the shank part 100 j by applying a force in a direction away from the shank part 100 j. Accordingly, the tool part 200 j can be easily detached from the shank part 100 j.

Further, in the ninth embodiment, while the shank part 100 i is configured to be rotated clockwise when seen from the screw head section 401, in the embodiment, the shank part 100 j is configured to be rotated counterclockwise when seen from the screw head section 401. Directions in which the shank parts 100 i and 100 j are rotated differ according to the friction stir welding apparatus. However, as described in the ninth embodiment and this embodiment, design changes of the shank parts 100 i and 100 j and the tool parts 200 i and 200 j may be performed according to the rotational direction of the friction stir welding apparatus.

Further, a plurality of configurations of the increased hole diameter section 142, the hexagonal frustum-shaped concave section 121 and the hexagonal frustum-shaped convex section 211, the hexagonal frustum-shaped convex section 111 and the hexagonal frustum-shaped concave section 221, the conical frustum concave section 122 and the conical frustum convex section 212, the key 131 and the key groove 232, the conical frustum convex section 112 and the conical frustum concave section 222, the key groove 132 and the key 231, the serrated shape 151 and the serrated shape 251, and the serrated convex section 161 and the serrated concave section 262 of the fifth to tenth embodiments may be appropriately selected and combined with each other. In addition, even in the ninth and tenth embodiment, like the fifth embodiment, the tool parts 200 i and 200 j can be attached to the shank parts 100 i and 100 j using the screw 400 e, and further, the tool parts 200 i and 200 j can be detached from the shank parts 100 i and 100 j using the tool part detachment screw 450 e.

Hereinafter, an eleventh embodiment of the present invention will be described. As shown in FIG. 30, the tool for friction stir welding 10 k according to the eleventh embodiment of the present invention includes a shank part 100 k, a tool part 200 k and a lid section 500.

As shown in FIGS. 30 to 32, a dovetail groove section 172 recessed in a trapezoidal shape and extending in the direction perpendicular to the axis of rotation 11 is formed at a front end that is an upper end of a shank part 100 k of FIG. 30. One end of the direction perpendicular to the axis of rotation 11 of the dovetail groove section 172 is opened in an outer periphery direction of the shank part 100 k by a lid-attaching cutout 181 having a shape corresponding to a shape of a lid section 500. The other end in the direction perpendicular to the axis of rotation 11 of the dovetail groove section 172 terminates at the inside of the shank part 100 k without reaching the outer periphery of the shank part 100 k. The lid-attaching cutout 181 has a pair of lid-attaching screw hole sections 145. The shank part 100 k has a tool part detachment screw hole section 146 formed from an end portion of the dovetail groove section 172 that terminates at the inside of the shank part 100 k to the outer periphery of the shank part 100 k. Both of the lid-attaching screw hole section 145 and the tool part detachment screw hole section 146 have grooves formed at inner periphery thereof.

As shown in FIGS. 30 to 32, a dovetail-shaped section 271 having a shape corresponding to a shape of the dovetail groove section 172 of the shank part 100 k and protruding in a trapezoidal shape is formed at the bottom section of the tool part 200 k. Further, in the embodiment, a dovetail-shaped section may be formed at the shank part 100 k, and a dovetail groove section may be formed in the tool part 200 k.

As shown in FIGS. 30 and 31, the lid section 500 has a shape corresponding to a shape of the lid-attaching cutout 181 of the shank part 100 k. The lid section 500 has a screw hole section 501 formed at a position corresponding to the lid-attaching screw hole section 145 of the shank part 100 k.

Hereinafter, an action of a tool for friction stir welding 10 k of the embodiment will be described. When the friction stir welding is performed using the tool for friction stir welding 10 k, as shown in FIGS. 31 and 32, the dovetail groove section 172 of the shank part 100 k and the dovetail-shaped section 271 of the tool part 200 k are fitted to each other. The dovetail groove section 172 extends in the direction perpendicular to the axis of rotation 11. For this reason, the tool part 200 k can slide with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k while movement of the tool part 200 k with respect to the shank part 100 k in the direction parallel to the axis of rotation 11 of the shank part 100 k is restricted. The dovetail-shaped section 271 is inserted into the dovetail groove section 172 until the dovetail-shaped section 271 abuts the end portion of the dovetail groove section 172 that terminates at the inside of the shank part 100 k.

In a state in which the dovetail groove section 172 and the dovetail-shaped section 271 are fitted to each other, the lid section 500 is attached to the lid-attaching cutout 181 by a lid section attachment screw 601. As the lid section attachment screw 601 is attached, the tool part 200 k cannot slide with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k, and the tool part 200 k is fixed to the front end of the shank part 100 k. Further, a release agent such as BN or the like is applied to the dovetail groove section 172, the dovetail-shaped section 271 and the lid section 500 that come in contact with each other to effectively prevent burning.

When the tool part 200 k is detached from the shank part 100 k, since the lid section 500 is detached from the shank part 100 k, a tool part detachment screw 602 is screwed into the tool part detachment screw hole section 146, and a force is applied to the dovetail-shaped section 271 of the tool part 200 k at the front end of the tool part detachment screw 602, even when the tool part 200 k is hard to remove, the tool part 200 k can be easily detached from the shank part 100 k.

In the embodiment, the tool for friction stir welding includes the tool part 200 k abutting the workpiece while rotating, the shank part 100 k configured to fix the tool part 200 k to the front end and rotated together with the tool part 200 k, and the lid section 500 fixed to the lid-attaching cutout 181 in which the tool part 200 k and the shank part 100 k come in contact with each other. The dovetail-shaped section 271 protruding in the trapezoidal shape and the dovetail groove section 172 recessed in the trapezoidal shape are formed at portions of the tool part 200 k and the shank part 100 k in which the tool part 200 k and the shank part 100 k come in contact with each other such that the tool part 200 k can slide with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k while movement of the tool part 200 k with respect to the shank part 100 k in the direction parallel to the axis of rotation 11 of the shank part 100 k is restricted because the tool part and the shank part are fitted to each other. After the dovetail-shaped section 271 and the dovetail groove section 172 of the tool part 200 k and the shank part 100 k are fitted to each other, as the lid section 500 is fixed to the lid-attaching cutout 181 in which the tool part 200 k and the shank part 100 k come in contact with each other to restrict slide movement of the tool part 200 k with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k, the tool part 200 k is fixed to the front end of the shank part 100 k.

For this reason, when the lid section 500 is fixed to the lid-attaching cutout 181, since movement of the tool part 200 k with respect to the shank part 100 k in the direction parallel to the axis of rotation 11 of the shank part 100 k is restricted by the dovetail-shaped section 271 and the dovetail groove section 172 that are fitted to each other and slide movement of the tool part 200 k with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k is restricted by the lid section 500, upon rotation of the shank part 100 k, fixation of the tool part 200 k and the shank part 100 k can be reliably prevented from being loosened, and the tool part 200 k can be reliably prevented from falling out of the shank part 100 kMeanwhile, when the lid section 500 is detached, even though the dovetail-shaped section 271 and the dovetail groove section 172 are fitted to each other, since the tool part 200 k can move with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k, the tool part 200 k can be easily detached from the shank part 100 k.

In addition, according to the embodiment, the tool part detachment screw hole section 146 configured to attach the tool part detachment screw 602 by applying a force such that the tool part 200 k slides with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k when the dovetail-shaped section 271 and the dovetail groove section 172 of the tool part 200 k and the shank part 100 k are fitted to each other and the lid section 500 is not fixed to the lid-attaching cutout 181 in which the tool part 200 k and the shank part 100 k come in contact with each other. Accordingly, as the tool part detachment screw 602 is attached to the tool part detachment screw hole section 146 and a force is applied by the tool part detachment screw 602 such that the tool part 200 k slides with respect to the shank part 100 k in the direction perpendicular to the axis of rotation 11 of the shank part 100 k, even when the tool part 200 k is hard to remove, the shank part 100 k can be more easily detached.

Further, the present invention is not limited to the embodiments but a detachment/attachment method may be modified in various forms, for example, by forming the tool part detachment screw hole section 146 as a through-hole with no groove, forming a screw hole section in the tool part and screwing the screw thereinto to fix the dovetail-shaped section 271, and so one.

INDUSTRIAL APPLICABILITY

According to the tool for friction stir welding of the one aspect and the other aspects of the present invention, fixation between the tool part and the shank part can be prevented from being loosened, the tool part can be reliably prevented from falling out of the shank part, and the tool part can be easily detached from the shank part.

REFERENCE SIGNS LIST

10 a to 10 k . . . tool for friction stir welding; 11 . . . axis of rotation; 100 a to 100 k . . . shank part; 111, . . . hexagonal frustum-shaped convex section; 112 . . . conical frustum convex section; 121 . . . hexagonal frustum-shaped concave section; 122 . . . conical frustum concave section; 124 . . . columnar concave section; 131 . . . key; 132 . . . key groove; 141 . . . hole section; 142 . . . increased hole diameter section; 144 . . . groove; 145 . . . lid-attaching screw hole section; 146 . . . tool part detachment screw hole section; 151 . . . serrated shape; 153 . . . vertical surface; 161 . . . serrated convex section; 163 . . . vertical surface; 172 . . . dovetail groove section; 181 . . . lid-attaching cutout; 200 a to 200 k . . . tool part; 201 . . . shoulder; 202 . . . probe; 205 . . . base section; 211 . . . hexagonal frustum-shaped convex section; 212 . . . conical frustum convex section; 213 . . . collar; 221 . . . hexagonal frustum-shaped concave section; 222 . . . conical frustum concave section; 231 . . . key; 232 . . . key groove; 241 . . . screw hole section; 244 . . . groove; 251 . . . serrated shape; 253 . . . vertical surface; 262 . . . serrated concave section; 263 . . . vertical surface; 271 . . . dovetail-shaped section; 300 . . . cap part; 301 . . .cap part inner surface; 302 . . . reduced diameter section; 400 e to 400 j . . . screw; 401 . . . screw head section; 402 . . . screw front end portion; 404 . . . groove; 450 e, 450 j . . . tool part detachment screw; 451 . . . screw head section; 452 . . . screw front end portion; 454 . . . groove; 460 . . . nut; 500 . . . lid section; 501 . . . screw hole section; 601 . . . lid section attachment screw; 602 . . . tool part detachment screw. 

1. A tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a cap part configured to cover the tool part and the shank part, wherein portions in the tool part and the shank part at which the tool part and the shank part contact each other have at least one from between a convex section and a concave section, in order to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction around the axis of rotation of the shank part is restricted, by the convex section and the concave section of the tool part and the shank part being fitted to each other, and after the convex section and the concave section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part, by the tool part and the shank part being covered by the cap part.
 2. A tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a screw having a groove formed at its outer periphery thereof for fixing the tool part to the front end of the shank part, wherein portions in the tool part and the shank part at which the tool part and the shank part contact each other have at least one from between a convex section and a concave section, in order to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction around the axis of rotation of the shank part is restricted, by the convex section and the concave section of the tool part and the shank part being fitted to each other, the shank part has a shank part hole section wherein the screw is capable of reaching the tool part fixed to the front end of the shank part passing through the shank part, the tool part has a tool part screw hole section having a groove, at an inner periphery, meshing with the groove of the outer periphery of the screw passing through the shank part hole section, and after the convex section and the concave section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part, by the groove of the outer periphery of the screw passed through the shank part hole section meshing with the groove of the inner periphery of the tool part screw hole section.
 3. The tool for friction stir welding according to claim 2, having a groove with an inner diameter larger than an inner diameter of the tool part screw hole section in an inner periphery of the shank part hole section, and capable of screwing in a tool part detachment screw having a groove on its outer periphery meshing with the groove of the inner periphery of the shank part hole section.
 4. The tool for friction stir welding according to claim 2, wherein the groove of the outer periphery of the screw and the groove of the inner periphery of the tool part screw hole section are formed such that the screw moves in an inward direction of the tool part screw hole section when the screw is rotated in the same direction as the rotational direction of the shank part.
 5. The tool for friction stir welding according to claim 1, wherein the convex section is a shape protruding in either a polygonal conical shape or a polygonal frustum shape, and the concave section is a shape recessed in either a polygonal conical shape or a polygonal frustum shape. 6-11. (canceled)
 12. The tool for friction stir welding according to claim 2, wherein the convex section is a shape protruding in either a polygonal conical shape or a polygonal frustum shape, and the concave section is a shape recessed in either a polygonal conical shape or a polygonal frustum shape.
 13. The tool for friction stir welding according to claim 1, wherein the convex section is a protruding shape as a key, and the concave section has a recessed shape as a key groove.
 14. The tool for friction stir welding according to claim 2, wherein the convex section is a protruding shape as a key, and the concave section has a recessed shape as a key groove.
 15. The tool for friction stir welding according to claim 1, wherein the convex section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and the concave section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation.
 16. The tool for friction stir welding according to claim 2, wherein the convex section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and the concave section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation.
 17. The tool for friction stir welding according to claim 2, wherein the convex section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation, and the concave section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and further provided with a nut having a groove at its inner periphery meshing with the groove of the outer periphery of the screw, the nut having an outer diameter larger than an inner diameter of the shank part hole section, wherein the screw passes through the nut while the groove of the outer periphery of the screw and the groove of the inner periphery of the nut are meshed with each other, the convex section and the concave section of the tool part and the shank part are fitted to each other, and after the groove of the outer periphery of the screw passing through the shank part hole section is meshed with the groove of the inner periphery of the tool part screw hole section, in a state in which the shank part is disposed between the tool part and the nut, the tool part is fixed to the front end of the shank part by the nut being rotated in a direction in which the nut and the tool part approach each other, and the tool part is detached from the front end of the shank part by the screw being rotated in a direction in which surfaces perpendicular to the direction around the axis of rotation of the serrated shapes fitted to each other separate from each other, after the nut is rotated in a direction in which the nut and the tool part recede from each other.
 18. The tool for friction stir welding according to claim 2, wherein the convex section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to a direction around the axis of rotation, and the concave section has a serrated shape including a surface parallel to the axis of rotation of the shank part and perpendicular to the direction around the axis of rotation, and after the screw is removed from the tool part screw hole section and the shank part hole section, a tool part detachment screw having a groove at its outer periphery meshing with the groove of the inner periphery of the tool part screw hole section passes through the shank part hole section, and the groove of the outer periphery of the tool part detachment screw is meshed with the groove of the inner periphery of the tool part screw hole section, and the tool part is detached from the front end of the shank part by the tool part detachment screw being rotated in a direction in which surfaces perpendicular to the direction around the axis of rotation of the serrated shapes fitted to each other separate from each other.
 19. A tool for friction stir welding comprising: a tool part abutting a workpiece while being rotated; a shank part configured to fix the tool part to a front end of the shank part and be rotated together with the tool part; and a sliding restriction member fixed to a portion at which the tool part and the shank part contact each other, wherein a portion of the tool part and the shank part in which the tool part and the shank part contact each other have at least one from between a dovetail-shaped section protruding in a trapezoidal shape and a dovetail groove section recessed in a trapezoidal shape, the dovetail-shaped section protruding in a trapezoidal shape and the dovetail groove section recessed in a trapezoidal shape enabling slide movement of the tool part with respect to the shank part in a direction perpendicular to an axis of rotation of the shank part while movement of the tool part with respect to the shank part in a direction parallel to the axis of rotation of the shank part is restricted by the dovetail-shaped section and the dovetail groove section of the tool part and the shank part being fitted to each other, and after the dovetail-shaped section and the dovetail groove section of the tool part and the shank part are fitted to each other, the tool part is fixed to the front end of the shank part so as to restrict slide movement of the tool part with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part, by the sliding restriction member being fixed to the portion at which the tool part and the shank part contact each other.
 20. The tool for friction stir welding according to claim 19, further comprising a detachment member receiving section capable of having attached thereto a detachment member for applying a force such that the tool part slides with respect to the shank part in the direction perpendicular to the axis of rotation of the shank part when the dovetail-shaped section and the dovetail groove section of the tool part and the shank part are fitted to each other and the sliding restriction member is not fixed to the portion at which the tool part and the shank part contact each other. 